1. Field of the Invention
The present invention relates generally to an antenna, and more particularly to a planar inverted-F antenna (PIFA) used in a portable electronic device.
2. Description of the Prior Art
With the development of wireless communication, more and more portable electronic devices, for example note book, install an antenna system for working in a Wireless Local-area Network (WLAN). Transmitting and receiving signals plays an important role in wireless communication process. In recent years, a majority of WLAN bases on Bluetooth technical standard or 802.11 technical standard. Antenna in Bluetooth technical standard bases on 2.4 GHz frequency band, and in 802.11 technical standard bases on 2.4 GHz and 5 GHz. So, antenna in notebook mostly works in the above frequency bands at the present time.
However, user would not satisfy a portable wireless communication devices only working in WLAN in the future. It's desired to make portable wireless communication device working in Wireless Wide-area Network (WWAN). The portable wireless communication device working in WWAN can work and entertain in more broad area. WWAN adopts two techniques, GSM and CDMA at present. However, a portable wireless communication device can work in GSM unless it has an antenna working in the frequency band of GSM. Antennas in notebook and other portable wireless communication device mostly work in 2.4 GHz frequency and 5 GHz frequency now. However, antennas of the mobile phone working in GSM mostly cannot be set in notebook or other portable wireless communication device because of size or power.
For example, China Patent No. 2689482Y discloses a PIFA capable of working on three frequency bands. The antenna includes three radiating elements, respectively operating at 1800 GHz, 900 MHz, and 2450 MHz. So, the antenna can be set in notebook or other portable wireless communication device for working in GSM. However, this antenna adopts solid structure, that is, the radiating elements, connection element, and grounding element respectively locate in different planes. Complex configuration and taking up more space result in the antenna going against industrialization manufacture, wasting cost and breaching trend of miniaturization development of antenna.
Hence, in this art, a planar inverted-F antenna to overcome the above-mentioned disadvantages of the prior art will be described in detail in the following embodiment.